Processes for the recovery and isolation of immunoglobulins G, A or M are known, e.g., U.S. Pat. Nos. 3,597,409 and 3,808,189.
It has been established that elevated levels of immunoglobulins M or A in fetal serum is indicative of chronic intrauterine or acute perinatal infections. Deficiencies in levels of IgG, IgA or IgM in older patients may be determined by this method.
At present, the most common commercially available system for determining immunoglobulin levels is the radial immunodiffusion plate. These plates are sold by a number of companies including Hyland, Kallestad, Meloy and Behring under as many different trade names. In this method specific antisera are incorporated into agar or agarose and, as the sample diffuses into the gel, an antigen-antibody precipitin ring is formed. The diameter of the ring is related to the concentration of the antigen. Generally, the times required for development of the rings are 24 to 48 hours which constitutes a major disadvantage particularly in the prenatal field. In contrast to the above, the test system of the present invention provides a result immediately upon completion of the test.
Diagnostic reagents formed by chemically coupling or combining a serologically determinant material to polymeric carrier particles of varying particle size, including latex, particles, are well-known, e.g., U.S. Pat. Nos. 3,882,225; 3,857,931; 3,825,525; 3,639,558; 3,565,987; 3,553,310; 3,407,076; 3,236,732; 3,096,250; Netherlands Pat. No. 7,201,308; and British Pat. No. 1,257,263. Latex particlegamma globulin suspensions have been used in the serologic diagnosis of rheumatoidarthritis, American Journal of Medicine, 21: 888-892 (1956).